bpf: Add missed maybe_wait_bpf_programs() for htab of maps

When doing batched lookup and deletion operations on htab of maps,
maybe_wait_bpf_programs() is needed to ensure all programs don't use the
inner map after the bpf syscall returns.

Instead of adding the wait in __htab_map_lookup_and_delete_batch(),
adding the wait in bpf_map_do_batch() and also removing the calling of
maybe_wait_bpf_programs() from generic_map_{delete,update}_batch().

Signed-off-by: Hou Tao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: Hou Tao

kernel/bpf/syscall.c

@@ -1758,7 +1758,6 @@ int generic_map_delete_batch(struct bpf_map *map,
 
 	kvfree(key);
 
-	maybe_wait_bpf_programs(map);
 	return err;
 }
 
@@ -1817,7 +1816,6 @@ int generic_map_update_batch(struct bpf_map *map, struct file *map_file,
 	kvfree(value);
 	kvfree(key);
 
-	maybe_wait_bpf_programs(map);
 	return err;
 }
 
@@ -5031,8 +5029,10 @@ static int bpf_map_do_batch(const union bpf_attr *attr,
 	else
 		BPF_DO_BATCH(map->ops->map_delete_batch, map, attr, uattr);
 err_put:
-	if (has_write)
+	if (has_write) {
+		maybe_wait_bpf_programs(map);
 		bpf_map_write_active_dec(map);
+	}
 	fdput(f);
 	return err;
 }